Adjustable valve for variable flows and a method for reducing flow through a valve

ABSTRACT

A fluid valve comprises a fluid conduit and a flow reducing device. The fluid conduit includes a fluid input end and a fluid output end. The flow reducing device comprises a first fluid passage and is configured to adjust the width of the first fluid passage. The first fluid passage has a narrow width over an extended flow distance that is delimited by internal walls that cause a pressure gradient in fluid passing through the first fluid passage. The flow reducing device further comprises a second fluid passage having a narrow width over an extended flow distance that is delimited by internal walls. The first fluid passage and the second fluid passage are parallel to each other. The flow reducing device further comprises a plurality of damping elements having surface portions parallel to each other. The facing surface portions of adjacent pairs of said damping elements define the internal walls delimiting the first and second fluid passages.

RELATED APPLICATIONS

The present application is a 35 U.S.C. §371 national phase applicationof PCT International Application No. PCT/SE01/02359, having aninternational filing date of Oct. 26, 2001, and claiming priority toSweden Patent Application No. 0003886-9, filed Oct. 26, 2000, and SwedenPatent Application No. 0004146-7, filed Nov. 14, 2000, the disclosuresof which are incorporated herein by reference in their entireties. Theabove PCT International Application was published in the Englishlanguage and has International Publication No. WO 02/35157 A1.

FIELD OF THE INVENTION

The present invention relates to a valve for variable flows, andparticularly to a valve adapted to provide air-flows within a wide flowrange, with limited generation of noise.

BACKGROUND

Many properties, for instance private houses and offices, are todaydevised with built-in ventilation systems in order to provide a betterin-door climate for the residents and employees. In many presentventilation systems the air-flow is however the same independent of theneed for ventilation, that is independent of if e.g. a room is filledwith people or not. These ventilation systems therefor cause unnecessaryconsumption of energy and raised energy costs. In order to satisfy thedemands of the future of lowered energy costs the air-flow has to bereduced extensively when few or no people are present, and be able towork with high flows when many people are present. The ventilationsystem therefore has to be devised with valves capable of within a wideflow range, without causing disturbing noise for that reason. The flowhas to be adjusted to the real need for ventilation but at the same timesatisfy the hygiene limits regarding temperature, CO₂ concentration,draft and a low sound level. By providing cooled air (16–17° C.) in away that does not cause a resulting draft, in combination withcontrolling of the energy supply to heat radiators at the windows meansthat it is possible to obtain an optimal solution for the in-doorclimate throughout the year. This way excess heat from people, computersand incoming sunlight can be controlled without the need for cooledbaffles or large amounts of air. This brings about that supply airterminals must be able to spread the cooled air in a way that does notcause a draft and does not cause the sound level to exceed given limitswhen the flow is reduced to a minimum of a few liters per second.

Among the ventilation systems known today there is no system capable ofmeeting the requirements above. In many ventilation systems the air-flowis adjusted for instance by means of a conventional damper, such as athrottle valve. When reducing the air-flow in these systems asignificant pressure difference occurs over a very short distance at theedge of the plate, which gives rise to a considerable amount ofturbulence, i.e. a powerful sound is generated over the edge of theplate. In order to lower the sound level in the room to an acceptablelevel, i.e. to approximately 30 dB(A), a silencer is therefore needed.Furthermore, a throttle damper cannot reduce the air-flow efficientlysince there will be a small open gap between the plate and the housingof the damper even in a closed state. There are throttle dampersarranged with a rubber sealing but these are not advantageous to usesince they demand actuators with high torque.

If a conventional supply air terminal, devised for stationary flows, isused together with a throttle damper in order to obtain ventilationadaptable to the current need using cooled air, the air-speed in theterminal would be so low at small flows that a cold air dropping effectwill occur, i.e. that air pours out of the ventilation system withoutbeing spread in an adequate manner in the room. This is a problem forinstance in certain conference installations were conferenceparticipants placed in the vicinity of the ventilation device experiencethat cold air is blown upon them, whereas participants located at adistance from the device will not experience any ventilation at all.Consequently, this is an effect of the air not being spread in anoptimum way.

The need for cooling work facilities has increased enormously duringrecent years, which has led to the repeated braking of energyconsumption records during the summer months. Even during the otherparts of the year the need for cooling is considerable due to the everincreasing use of computers and other electronic equipment. The mostcommon way of controlling the indoor temperature has been to use heatelements and cooling baffles in places with high requirements ontemperature stability. Fancoil, a cooling device with a built-in fan isanother solution. These solutions demand that a supply system for acirculating cooling medium is arranged in the facility, which is bothenergy demanding and brings about a high investment cost. Another way ofsolving the cooling need is to supply cooled air. This puts a highdemand on the mixing in of the cooled air into the present warmer air inthe room, so that a cold draft does not result. Furthermore, the flow ofcool air has to be varied in relation to the existing need, so that theroom does not get too cold. A supply air terminal for this purpose hencehas to be able to increase and reduce the flow without causing cool airto simply drop down, as previously explained. Because of thesedifficulties in the prior art to cope with these demands, it has onlybeen possible to supply input air which is a few degrees cooler than theambient room temperature. Because of this, large amounts of air need tobe supplied in order to obtain a sufficient cooling effect, which inturn means that the ducts or conduits of the entire ventilation systemhas to be dimensioned thereafter. Furthermore, it has not been possibleto reduce the flow to a desired extent of only a few liters per seconddue to the resulting dropping cold air and damping noise.

One example of the prior art technique is shown in FIG. 1. The valve inthis device comprises a tube 1 with a conduit 2 for input of air,preferably arranged with an output orifice 3 at a ceiling 4. A flowreducing device 5 is further devised with a surface 6 facing a orifice 3of the tube. The supply flow of air through the tube 1 mainly occurs inthe directions of arrows a and b. The air-flow is adjusted by raising orlowering the flow reducing device 5, which is illustrated by thebi-directional arrow in the figure, for opening of the gap between thesurface 6 and the orifice 3. A dashed line in the figure illustratesthat the flow reducing device 5 in some way is fixed to the tube 1 or tothe ceiling 4, and is adjustable in different height positions.Actuators for adjusting the air-flow can be applied with some form ofdriver means, wherein the position preferably is adjusted by means ofpneumatics under control of mechanical temperature sensors. In a simplerembodiment the actuator can be manually adjustable, for instanceconstituted by a screw in an oblong hole.

A disadvantage with the solution according to FIG. 1 is that, as with athrottle damper, or an iris damper for that matter, reduction isachieved in one point, or rather at the verge of the orifice 3. A largereduction with very small air-flows, i.e. when the plate is upraised,therefore brings about an increased sound level because of theturbulence which is formed alongside the edges of the orifice 3 duringthe powerfull pressure change. In order to avoid this the distancebetween the tube 1 and the flow reducing device 5 is usually limited byuse of spacers, wherein the air-flow cannot be completely reduced.Hence, the air-flow cannot be completely adjusted based on the need forventilation, wherein it is hard to obtain the desired saving effects.

Another disadvantage with the device according to FIG. 1 is that a flowregulation is carried out with a pressure from a supply air actingtowards the adjustable flow reducing device 5. When reducing the flow,i.e. when the flow reducing device 5 is brought towards the orifice 3,the flow reducing device will hence work towards the air pressurepresent in the air conduit in the tube 1, caused by both static anddynamic pressure. This means that a certain force will be needed forreducing the flow, and that for dynamic adjustment an engine is neededwhich engine is devised such that it is capable of exercising thenecessary work. However, it is desirable that said engine is as quite aspossible, since it is placed inside an office facility or the like, andis adjusted dynamically dependent on certain given parameters. At thesame time, one realises that the higher work the engine has to exercise,the more sound is generated.

SE 442669 discloses a supply air terminal wherein a cone-shaped flowreducing device is arranged to be brought closer or farther away from aninlet tube opening for the purpose of regulating the flow. The disclosedsolution uses the same principles as the prior art according to FIG. 1,and hence suffers from the same drawbacks.

DE 2105077 relates to a self-regulating valve for constant flows,adapted to compensate for variations in the input air pressure. A springmechanism is used such that in case of a pressure drop in the input airthe damper opening is regulated in order to help maintain a steady flow.

SE 516616 discloses an air distributor, devised to be manually operatedto direct the divergence of the output beam of air. A blade ring ismounted in a stationary position in relation to an outermost tube whichincludes a collar. In the air distributor there is a displaceableseparate cylinder pipe which is used for guiding air and which can bebrought into different regulation positions in relation to thestationary blade ring. The apparatus is not devised for, nor capable of,regulating the output flow, but is devised to control the divergence ofthe output beam by displacing the separate cylinder pipe such that avariable portion of the input air is passed through the blade ring, an acomplementing portion is passed outside the separate cylinder pipe.

Another problem associated with ventilation systems of the prior art isthe implementation of fire dampers. In order to prevent smoke and hotgases from spreading in the ventilation system, causing damage orpotentially spreading a fire, basically every ventilation system oftoday is devised with some form of shut-off function in the form of firedampers. Therefore, both a flow regulating device and a fire damper isusually located in the same duct, since no satisfying solution tocombine the two has been provided. A fire damper must be capable ofcompletely closing off the duct, which means that if a throttle valve isused it has to be provided with a rubber sealing around its damperblade. The drawbacks of such a device are many due to the frictioncaused. Both the rubber sealing and the actuator, which is oftenexercised every day in order to check its function, will become worn outprematurely, and the closing speed of the fire damper will be slow dueto the dry friction.

U.S. Pat. No. 4,397,223 relates to a reciprocating actuator for a valvein the form of an air diffuser. The actuator is devised to react to fireor high heat, and to close the valve in such case. Since the spring usedto close the valve in case of the aforementioned situations has to workagainst the air pressure in the connecting pipe, a latch mechanism hasbeen provided to prevent the valve from opening in case the pressureexceeds the closing force of the spring.

U.S. Pat. No. 2,367,104 describes an air distributor having a damperconstruction with two flat cones for distributing air supplied from thedevice. A first cone is used as a damper for reducing the air flow byadjustment of the output opening of the device. The other cone is notpassed by the output air, but merely uses the speed of the output air tosuck air present in the room through the space between the two cones, inorder to cause an injection of the fresh air with the present air.

The present invention relates to a valve which fulfils the requirementsabove and which does not display the disadvantages associated with theprior art.

SUMMARY OF THE INVENTION

Consequently, the invention relates to a fluid valve for variable flowsof for example air, comprising a tube with an input opening and anoutput opening, a flow reducing device having a damping surface facingsaid output opening for adjustment of the air flow through said tube,and an actuator for variable adjustment of the distance between thedamper surface of flow reducing device and said output opening. The tubehas an outer damper flange, projecting from said output opening. Saiddamper flange preferably has a flange surface extending between the edgeof the output opening of the tube and the outer edge of the damperflange, wherein a flow distance having a given height is defined betweenthe limiting surfaces constituted by said flange surface and said dampersurface. In one embodiment said flange surface and said damper surfaceare substantially parallel, alternatively the distance between saidflange surface and said damper surface decreases from the edge of theoutput end to said outer edge.

At large damping the height between the damper surface and the flange issmall, particularly in relation to the length of said flow distance, andthereby a retardation of the air flowing there through is obtained overan extended section. Therewith, a pressure reduction is obtained whichyields minimum generation of sound, particularly in comparison withsimple dampers where basically the entire pressure reduction is obtainedover an edge.

In one embodiment the valve comprises a damper disc with a centralrecess, which damper disc is arranged substantially parallel between theflange and the flow reducing device in order to delimit a portion ofsaid given height, and means for limiting the height of the delimitedportion to a predetermined maximum height. In one embodiment, where thevalve has a circular cross section said damper disc is preferablyring-shaped, wherein said recess forms an inner diameter preferablycorresponding to or exceeding the inner diameter of tube, whereas theouter diameter of the damper surface essentially corresponds to thediameter of the flange.

At a flow setting where said given height is smaller than said maximumheight, said damper disc is placed adjacent one of said limitingsurfaces, either directly against the flange or the flow reducingdevice, or against one or a couple of additional damper discs. At a flowsetting where said given height is larger than said maximum height, saiddamper disc is placed at said maximum height from said one of saidlimiting surfaces.

Preferably a plurality of damper discs are arranged in parallel betweenthe flange and the flow reducing device in order to delimit each oneportion of said given height, and means are provided for limiting theheight for each delimited portion to said maximum height. Theses meansfor limiting the height of the delimited portions preferably includescollapsing suspension means mounted to said flange.

The advantage with this arrangement is that the valve's total openingwith height y will be constituted of one or more sub openings with amaximum height x, where each sub opening has its own narrow flowdistance. Hence, the extended pressure reduction will be obtainedregardless of the size of the opening of the valve, wherein a minimumsound generation is obtained independent of the flow setting.

In the valve according to the present invention said tube comprises adynamic tube member with open ends, slideably arranged concentricallywith a stationary tube member, wherein said actuator is devised todisplace said dynamic tube member along the stationary tube member foradjustment of the distance between said output opening and said dampersurface.

An advantage with the valve according to this embodiment is that itneeds very small actuator forces, since the element which is moved uponopening and closing of the valve is a tube member with open ends whichis displaced in its axial direction. Thereby the air pressure will onlywork radially outwards against the envelope surface of the tube member,but will not counteract the movement of the tube member. Therewith asmall engine can be used with a low input effect so that it will operatequietly and with small power consumption.

Preferably said flow reducing device is arranged with spacer bars on afixed distance from said stationary tube member.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in greater detail below withreference to the accompanying drawings, in which

FIG. 1 shows a valve for variable flows according to the prior art;

FIG. 2A shows an embodiment for a valve for variable flows according tothe present invention;

FIG. 2B shows another embodiment for a valve for variable flowsaccording to the present invention;

FIG. 3 shows a different embodiment of the valve according to thepresent invention, devised with a damper flange;

FIG. 4 shows an embodiment of the invention with the funnel-shapedoutput opening;

FIG. 5 shows an embodiment of the invention, adapted for mountingbetween two tubes;

FIG. 6 shows an embodiment of the invention, devised with a stationarypressure reducing element 34 for nominal reduction of the air flow;

FIG. 7 shows an embodiment of the invention, wherein the total openingof the valve is split into sub openings dependent of the flow;

FIGS. 8 a and 8 b show an alternative embodiment of FIG. 7, devised forsimultaneous regulation of all sub-openings; and

FIGS. 9 a and 9 b show an embodiment similar to that of FIGS. 8 a and 8b, adapted for wall mounting.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention relates to a valve for variable air flows which iscapable of reducing the air-flow with minimum sound generation.

In FIG. 2A a valve according to the present invention is shown,comprising a tube 11 arranged e.g. at the ceiling 4 of a room, whichtube 11 forms a conduit 13 for flow of air. The tube comprises a firststationary tube member 11, preferably firmly arranged towards saidceiling 4 at the first open end 14 of the tube member. The stationarytube member has an open output opening 17 at the first end 14. An openinput opening 15 is arranged at the second end of the tube member 11,arranged for connection to a ventilation system (not shown) for supplyof air. Hence, the valve is devised for flow of air from said input end15, through the conduit 13, and out through said output opening 17.Furthermore, the valve comprises a flow reducing device 18 forregulation of the air flow out from the tube 11. Said flow reducingdevice 18 displays a surface 19 towards said output opening 17 of thetube 11. The surface 19 will hence force air from the tube 11 to flowout sideways in the direction of the arrows A and B wherein theventilation air will be guided out and spread in the room. It should benoted that the tube 11 and flow reducing device 18 in the valveaccording to the present invention each has a certain cross section,though not evident from the figure, and that the valve can be arrangedfor discharge of air through the entire circumference of the opening ofsaid output opening 17. The cross section is preferably circular, butmay of course just as well be triangular, square or of any other shape.The flow reducing device and the output opening 17 of the tube 11 aredisplaceable towards and away from each other, i.e. laterally as thevalve is illustrated in FIG. 2A, for regulation of the air flow. Thiscan be solved in many ways. One way is to arrange a non-adjustable,.i.e. stationary, tube member 11 in the tube, wherein the flow reducingdevice is movable for setting into different distances from the tubemember 11. An alternative is to have the flow reducing device 18 firmlyarranged to the ceiling 4, and to have a dynamic tube member 12displaceable towards or away from the flow reducing device 18. Yetanother way is to arrange a portion of the tube 11 in the form of afolded pipe like a bellow, so that said portion can be extracted andpressed together in order to displace the output opening 17 towards theflow reducing device 18. Such a folded portion may be devised between astationary 11 and a dynamic 12 tube member, or be connected with one ofits ends to the output end 14 of a stationery tube 11, such that thesecond end of the folded portion forms said output opening 17. Otheralternatives are discussed below, and they may of course also becombined.

In FIG. 2A and embodiment is illustrated wherein the tube 11 isconstituted of a stationary tube member 11, fixed firmly to the ceiling4 in some undisclosed manner. An actuator for regulation of the air flowis in its simplest embodiment a device arranged for adjusting thedistance of the flow reducing device 18 to the output opening 17 of thetube 11. In a simple way this may be achieved by arranging the flowreducing device 18 with protruding elements (not shown) on the dampersurface 19, which fits and engages with the inside of the tube 11 with acertain friction, e.g. caused by a rubber coating on the protrudingelements or on the inside of the tube 11. The flow reducing device 18may then be displaced into or out of the stationary tube member 11, e.g.manually, and then be retained in the selected position by means of saidfriction.

In one embodiment of the valve according to the invention, also shown inFIG. 2A, the actuator is automated and devised with driving means 22 atthe flow reducing device 18. Said driving means 22 is arranged to uselow speed to achieve a high torque, and is for example constituted by aDC engine, but any other driving means, such as step engine or pneumaticengine may also be used. In the embodiment illustrated in FIG. 2A thedriving means 22 of the actuator is devised to displace the flowreducing device 18 in relation to the tube 11 by means of a suitabletransmission 23,24,25 for regulation of the flow through the valve. Inthe illustrated embodiment the transmission of the actuator comprises arod 23 with an outer thread, which rod extends inside the dynamic tubemember 12 along its extension axis, preferably centrally in the conduit13. Said rod 23 is rotatable by means of said driving means 22.Furthermore, a nut member 24 having an inner thread is arrangedcentrally in the dynamic tube member 12, preferably connected to thedynamic tube member 12 by means of one or more fixation bars 25 which donot influence the air stream through the conduit 13 in any substantialway. The rod 23 is arranged through the nut member 24 in the threadedengagement. The transmission 23,24,25 is arranged such that rotation ofthe rod 23 causes rotation of the rod 23 in relation to the nut member24, rather than rotation of the flow reducing device 18 in relation tothe tube 11. Rotation of the flow reducing device 18 may e.g. beprevented by means of said protruding elements engaging with frictionwith the inner surface of the tube 11. By rotation of the rod 23, bymeans of the driving means 22 of the actuator, the flow reducing device18 is thereby brought, through displacement forces acting on the threadsof the nut member 24, to be displaced towards or away from thestationary tube member 11. In this way the damping, i.e. the distancebetween the output opening 17 and the surface 19, is controllable.

In FIG. 2A it is further illustrated how the valve according to presentinvention is devised with an outer damper flange 30, extending from thetube 11 essentially parallel to the surface 19 of the flow reducingdevice 18, which damper flange 30 forms a wing on the outside of theoutput opening 17 of the tube 11. As the tube member 11 and the flowreducing device 18 are displaced towards each other, the angle betweenthe flange surface 31 which the flange 30 faces towards the dampersurface 19 of the flow reducing device 18, and said damper surface 19,remains constant regardless of the flow setting. The embodimentincluding a damper flange 30 extending essentially parallel to the uppersurface 19 is based on the inventors' conviction that an optimum flowreduction with a minimum generation of sound is one that is caused by anextended damping, similar to the narrow passage in a hose. In such anarrow passage the constant friction towards the walls of the hose givesrise to a pressure fall between the input opening and the outputopening, wherein the pressure falls evenly between said openings. Sharpedges, on the other hand, were a sudden drop in pressure is generated,such as for instance in a throttle valve, lead to substantial turbulencewhich causes both noise and an under-pressure which counteracts theforce which has to be applied on the damper during throttling. By thearrangement with an projecting flange an extended flow distance out ofthe valve is obtained, which flow distance is mainly defined by thedistance between the edge 32 of the inner diameter of the tube 11 at theoutput opening 17, and the outer edge 33 of the flange 30, alternativelythe outer edge of the flow reducing device 18 if the flange extendsfarther than the flow reducing device 18. For valves were the tubediameter for the tube 11 displays a standard size in the range of 10–40centimetres, the length of said flow distance is within the range of1–20 centimetres and preferably between 4–10 centimetres, for example 7centimetres. Naturally, suitable dimensions of the flange 30 aredependent on the air pressure for which the valve is adapted.

Thanks to the distance between the limiting surfaces 31 and 19 beingessentially parallel, or somewhat tapered towards the outer edge 33, agradual change in the air pressure occurs wherein the air resistance orturbulence is distributed evenly along the entire flow distance withminimum generation of sound as a consequence. This is valid also for ahigh flow reduction with minimum flow. The embodiment with a taperedflow distance, i.e. were the distance between the surface 31 of theflange 30 and the surface 19 of the flow reducing device 18 decreasesoutwardly towards the edge 33, is adapted to counteract the radialvolume expansion of the flow zone, were said flow zone consequentlyrelates to the entire zone between the surfaces 31 and 19 in threedimensions. Since the surface of the flow zone between 31 and 19increases with the square of the radius out towards the edge 33, so doesthe volume if the limiting surfaces 31 and 19 are parallel. This wouldmean that the pressure fall would not be entirely evenly distributedbetween the inner edge 32 and the outer edge 33, but be higher towardsthe inner edge 32. The angle of the flange 30 against the flow reducingdevice 18 hence counteracts this phenomena. The angle of the flange 30towards the damping surface 19 is however relatively acute, preferablywithin the range of 0–20°. It is of course also possible to design theflange somewhat curved in relation to the damper surface 19, so that theangle between them decreases from the inner edge 32 to the outer edge33, at the same time as the distance between the flange 30 and thedamper service 19 decreases.

In FIG. 2B an embodiment of the present invention is illustrated,wherein the flow reducing device 18 is arranged at a fixed distance fromthe ceiling 4, and where instead the output opening 17 of the tube 11 isdisplaced towards or away from the flow reducing device 18. In the valveaccording to this embodiment, said tube comprises a first stationarytube member 11, firmly fixed in relation to the ceiling 4, an further asecond, dynamic tube member 12, arranged axially displaceable at thefirst tube member 11. The flow reducing device 18 is preferably firmlyattached to the stationary tube member 11 by means of spacer bars 21,which spacer bars define the maximum distance d which the seconddisplaceable tube member 12 can be displaced out of the stationary tubemember 11. As is evident from arrows A and B the spacer bars 21 shallnot be seen as hindering the air flow, but rather forming discretesupport means.

Preferably the dynamic tube member 12 is arranged inwardly of the firsttube member 11, as disclosed in FIG. 2B, therefore having an outerdiameter which does not exceed the inner diameter of the stationary tubemember 11. In an alternative embodiment the dynamic tube member 12 mayhowever be arranged outwardly of the stationary tube member 11. Saiddynamic tube member 12 also includes an input opening 16, facing thesame direction as input opening 15 of the stationary tube member, and anoutput opening 17 turned towards the output opening end 14 of thestationary tube member, respectively. The output end 17 of the dynamictube member 12, which furthermore constitutes the output end of saidtube 11,12, extends outside the output end 14 of the stationary tubemember 11 to a different extent in dependence of the damping of thevalve. The output end 14 of the stationary tube member is in oneembodiment adapted for fixed mounting onto the ceiling, or in a wall. Inone embodiment of the valve according to the invention, wherein thedynamic tube member 12 is devised inwardly of the stationary tube member11, said output end 14 is devised with an outer mounting flange 20,adapted for mounting towards the ceiling or the wall with suitablefastening means, such as screws, rivets, glue or the like.

In the figures showing the present invention the dynamic tube member 12is drawn at a distance inside the stationary tube member 11 in order tosimplify the figure. The radial distance between the tube members 11 and12 is however as a rule small enough to prevent air passage between thetube members 11 and 12, and at the same time large enough for thedynamic tube member 12 to be easily displaceable in both directionsinside the first tube member 11 in a way that provides minimum friction,unless the friction has a purpose of itself according to a previouslydescribed embodiment. The embodiment according to FIG. 2B is furtherarranged with a suitable actuator according to what has been describedabove.

The flange 30, which according to what has been described in relation toFIG. 2A is devised at the output opening 17, can be manufactured with anouter diameter 33 which runs outside the spacer bars 21, whereinsuitable recesses are formed in the flange 30, in which recesses spacerbars 21 are devised to run during flow regulation.

In the valve according to the embodiment with a dynamic tube member 12,the air flow is varied by using an actuator to vary the distance betweenthe output end 17 of the dynamic tube member 12 and the surface 19 ofthe flow reducing device 18, wherein a linear relation is obtainedbetween the actuator setting and the air flow out of the valve. Thepresent air pressure in the conduit 13 acts radially outwards towardsthe walls of the dynamic tube member 12. However, apart from certainfriction neither the static pressure caused by overpressure in the inputair through the input opening 16, nor the dynamic pressure caused by theair flow itself, acts with any force on the dynamic tube member 12 inthe axial direction. This means that control of the damping can be madewith very little force, which in turn means that both the effectrequired by driving means 22 arranged for the actuator, and the sound itgenerates, can be minimised.

FIG. 3 also displays an embodiment of a stationary pressure reducingelement 34, arranged at the inner envelope surface of the dynamic tubemember 12. Since it is mounted fixed to the dynamic tube member 12 it isin some sense moveable, but not in such a way that its affects on thepressure reduction is varied as a consequence of the position of thedynamic tube member 12 in relation to the flow reducing device 18. In anembodiment were the dynamic tube member 12 is arranged to run outwardlyof the stationary tube member 11, the stationary pressure reducingelement 34 is of course preferably arranged on the stationary tubemember 11. Characterising for the stationary pressure reducing element34 is that it defines a predetermined narrowing of the innercross-section area for the conduit 13, or the inner diameter of theconduit 13 in the case the tube 11,12 is cylindrical, over an extendeddistance in said conduit 13, whereby the “hose effect” according to theabove is obtained. In an embodiment adapted for ventilation tubes ofstandard sizes in the range of 10–40 cm diameter, the stationarypressure reducing element 34 defines an inner cross section area, whichis narrowed from the inner cross section area of the tube 11,12.Preferably the cross section area for the stationary pressure reducingelement 34 is 10–80 per cent of the inner cross section area of the tube11,12, over a distance of 5–50 cm. The dimension which is chosen isdependent on the air pressure of the incoming air to the valve, andwhich maximum pressure it is desired to have out in the room which thevalve supplies with air. The stationary pressure reducing element 34 isfurther preferably rounded at the flange 30 of the dynamic tube member12, in such a way that the opening 17 of the dynamic tube member 12towards the flow reducing device 18 increases gradually. Preferably saidrounding off displays a radius which is equal to the thickness of thestationary pressure reducing element 34. Furthermore, in this embodimentthe flow reducing device 18 is formed such that the surface 19 has apreferably symmetric raised portion 35, wherein the symmetry axis of theraised portion 35 coincides with the longitudinal axis of the dynamictube member 12. The stationary pressure reducing element 34 preferablyformed of a sound isolating material, such as plastic foam.

In one embodiment a sound isolating carpet 36 is also arranged on thesurface 19 of the flow reducing device 18. Said carpet includes, in oneembodiment, said raised portion 35 which is adapted to enclose thedriver means 22 of the actuator, and which is also formed with asuitable tapered tip adapted to the rounding off of the stationarypressure reducing element 34. Preferably the carpet 36 has a radialextension which essentially coincides with the outer edge 33 of theflange 30.

In one embodiment, illustrated in FIG. 6, the stationary pressurereducing element 34 is instead arranged at the flow reducing device 18,protruding centrally in the conduit 13 and essentially enclosing thedriver means 22 and the rod 23. The nut member 24 of the transmissionmay in this embodiment be arranged above the pressure reducing element34, or, as illustrated in FIG. 6, inside. This can be achieved byforming the pressure reducing element 34 in plastic foam or the like,and forming a slot for each fixation bar 25 which makes it possible forthe nut member 24 to run in a channel (not shown) under the pressurereducing element 34. Preferably the stationary reducing element 34 isformed with rounded ends according to FIG. 6, and may be integrated withthe isolating carpet 36. In this embodiment the stationary pressurereducing element 34 also forms the raised portion which covers drivermeans 22, corresponding to the raised portion 35 according to previouslydescribed embodiments. Also the pressure reducing element 34 accordingto the embodiment of FIG. 6 defines a narrowed inner cross section areain the conduit over an extended portion of the conduit 13, and thereforcauses said hose effect.

The pressure reducing element 34 is thus the static correspondent to theflow distance between the surfaces 19 and 31. At a large opening of thevalve, i.e. when the dynamic tube member 12 is displaced far into thestationary tube member 11, the extended flow limitation provided by thepressure reducing element 34 will cause a nominal pressure reduction. Atincreased flow reduction the contribution to the flow reduction of thewing 30, by being moved closer to the flow reducing device 18, willincrease and eventually take over. If the stationary pressure reducingelement 34 is formed according to the embodiment of FIG. 6, and also isrelatively short in comparison with the distance between the flowreducing device 18 and the stationary tube member 11, the reducingeffect which the stationary pressure reducing element 34 has to someextent be dependent of the position for the dynamic tube member 12. Onerealises though that for a rather extended pressure reducing element 34,for instance were the pressure reducing element 34 is about twice aslong as the distance between the flow reducing device 18 and thestationary tube member 11, as illustrated in the figure, the reductioncaused therefrom will not be dependent on the position of the dynamictube member 12 in any significant way, but will only give rise to saidnominal reduction. In accordance with the embodiment discussed above theflow reduction caused by the damping of the dynamic tube member 12towards the flow reducing device 18 will dominate for small valveopenings.

The extended flow reducers, comprising a dynamic flow reducer 30 and astatic flow reducer 34 are of course separately useable and are bothformed for minimum noise generation. In an embodiment were both theseare included, such as in FIG. 3, they will define the margin conditionsfor the valve. The static flow reducer 34 defines the maximum flowthrough the valve at a pre-determined air pressure of the air supplyinto the valve. This is defined both by the length of the flow reducer34 and by the inner cross section area defined by it in the conduit 13,and can thereby be designed based upon the existing need. The dynamicflow reducer 30 defines flow reduction upon damping, and its influenceof the flow reduction at a certain valve opening, i.e. the position forthe dynamic tube member 12 in relation to the flow reducing device 18,is mainly controlled by the length of the flange 30 from the inner edge32 to the outer edge 33.

FIG. 6 also illustrates a detail which in the same way can be combinedwith any of the embodiments illustrated in FIGS. 3–5, namely anisolation device 43 arranged at the flange 30. This isolation device 43can be used in combination with the carpet 36 or by itself, and isadapted to provide sound isolation for the flow.

In FIG. 4 an alternative embodiment of the invention is shown, havinglarge similarities with the embodiment of FIG. 3. However, the solutionaccording to FIG. 4 differs in the way that the flow reducing flange 30is devised with an opening angle towards the dynamic tube member 12,which opening angle differs from 90°, so that the output opening 17forms a funnel with gradually increasing opening. The raised portion 35on the flow reducing device 18 is further formed in a corresponding way,so that parallelism or a certain angle according to what has beendescribed with reference to FIG. 3, remains between the damper surface19 of the flow reducing device 18 and the damper surface 31 of theflange 30.

The valve according to the present invention, as embodied in FIGS. 2–4may advantageously be arranged in the ceiling of a room. The valve isthen devised such that the stationary tube member 11 is arranged in ahole in the ceiling such that the mounting flange 20 is arranged inparallel with and on the inside of the ceiling. A valve according to thepresent invention may however also be used for flow regulation in tubes,wherein no or very little generation of sound occurs. FIG. 5 shows avalve were a second tube 40 is devised tightly to the output end 14 ofthe stationary tube member 11. In the embodiment illustrated in FIG. 5the flow reducing device 18 has a surface 19 which is parallel ordevised with a certain angle in the previously described manner, withthe flange 30 of the dynamic tube member 12. The flow reducing device 18also has a second surface 41 facing away from the dynamic tube member12. In FIG. 5 this second surface 41 of the flow reducing device 18 isconically tapered in the direction away from the dynamic tube member 12.This surface 41 may however be formed in any other suitable way in orderto fit to the second tube 40. If the tube 40 is straight instead oftapered, the second surface 41 of the flow reducing device 18 may forinstance have a cylindrical shape. As is suggested by the figure theflow reducing device is preferably mounted to the second tube 40 with asuspension device 42 including a couple of discrete suspension elementsdevised not to hinder or disturb the air flow.

The arrangement of the flange 30 and the flow reducing device 18 is inthe embodiment of FIG. 5 similar to that of FIG. 4, with a funnel shapedincreasing output opening 17. One realises however that an arrangementaccording to FIG. 3 could also be used. Furthermore it is possible toadapted the embodiment according to FIG. 5 to the pure embodimentaccording to FIG. 2, that is without the extending flange 30. In suchcase one will still achieve the advantage of the flow regulation nothaving to be performed while exercising work against the air pressure.Furthermore, the construction according to FIG. 5 can of course besupplemented with the static flow reducer 34, or be used without it.

In an alternative embodiment to that of FIG. 5, the transition betweenthe tubes is applied at an angle. For such an angled embodiment thesurface 19 basically constitutes the end surface of the conduit 13 ofthe tube 11,12. The second tube 40 joint to a tube 11,12 is in thisembodiment devised to extend sideways from the opening 17 of the valve.With reference to FIG. 5 the tube 40 would then run essentiallyhorizontally, or at some other angle, outwardly in one or bothdirections from the valve. The tube 40 then engages the valve at thelower end 14 of the stationary tube member, and at the damper surface19, for example were a suspension device 42 is illustrated in FIG. 5.The driver means of the actuator in such an embodiment may be arrangedon the inside of the end surface 19 of the conduit 13, or on theoutside, with the recess made in the end surface 19 for the transmissionrod 23.

In FIG. 7 an embodiment of the present invention is showed, wherein thefeature of the extended damping has been developed another step. Inaccordance with was has been previously described an elongated dampingprovides the advantage that the retardation of the air occurs along anextended portion with distributed formation of turbulence, a so-called“hose effect”. This results in a soft retardation with considerably lessgeneration of sound than for example a throttle damper or an irisdamper, were the damping only occurs at the edge of the damper. Whenconsidering, for instance, the flow distance for arrow A in FIG. 2 b,one realises that the flow speed in the passage between surfaces 19 and31 is highest at the centre between these two surface since theretardation occurs against said surfaces. Furthermore, a person skilledin the art realises that the retardation increases the shorter thedistance between surfaces 19 and 31 is. A consequence thereof is thatwhen the distance between the surfaces increases, the influence of thehose effect will decrease, and basically disappear at some given valveopening. This brings about an increased sound generation, as thepressure reduction will essentially occur over the edge 32 of the outputopening 17 or at the outer opening at the edge 33. In FIG. 7 a solutionto this problem is illustrated. In this embodiment one or several damperdiscs 70,71 are arranged between the flange 30 and the flow reducingdevice 18. Each damper disc 70,71 is preferably constituted by aring-shaped planar disc, arranged essentially parallel to surfaces 31and 19, or if there is a small angle between the flow reducing device 18and the flange 30, substantially in the median of this angle. Eachdamper surface 70,71 discloses an inner diameter 75, which preferablycorresponds to or exceeds the inner diameter of the conduit 13 of thetube 11,12. The outer diameter 72 of the damper surface 70,71 preferablycorresponds to the outer edge 33 of the flange 30. Each damper surface70,71 is suspended in one or more suspension means 73,74 in the tube11,12 or the flow reducing device 18, or in damper discs 70,71 arrangedabove it. In FIG. 7 an embodiment is shown wherein the suspension means73,74 are mounted to the flange 30 on the tube, and the embodiment ofFIG. 7 is of the type having a displaceable tube member 12 in relationto a firmly arranged flow reducing devise 18. A person skilled in theart realises however that the specific features of this embodiment maylikewise be applied on an embodiment according to FIG. 2 a.

The suspension means 73,74 are devised such that they can collapse, i.e.they have a defined maximum length between two damper elements, but anundefined minimum length. By damper element is here meant the flange 30,the flow reducing device 18, and the intermediate damper discs 70,71.Such a collapsing suspension means 73,74 may for example be implementedas a screw which in at least one damper element runs essentially freelyin a recess, wherein the screw, on the outer side of the damper element,is devised with a nut which cannot pass though said recess, and therebydefines said maximum length. In a simpler embodiment the suspensionmeans 73,74 may be implemented as a chain or a string, which by naturecollapses in the absence of pulling forces. In the illustratedembodiment, all suspension means 73,74 are mounted to the flange 30. Inpractice, the suspension means for each damper disc 70,71 could howeverbe mounted through its suspension means to the damper element closestabove, whether it is a different damper disc 70,71 or the flange 30.Each suspension means 73,74 defines by each maximum length a maximumheight x between two surfaces. This maximum height x is adjustable independence of the working pressure for the supply air, dimensions of thevalve, and so on, by screwing down the nut on the screw 73,74,shortening the string or chain 73,74, or in some other way. Preferablyall suspension means 73,74 define the same maximum distance x. At thesame time the height between the surface 31 of the flange 30 and thedamper surface 19 of the flow reducing device 18 defines the totalopening y, under the ideal presumption that the damper discs 70,71 areinfinitesimally thin. In reality the total opening is y minus the addedthickness of the damper discs 70,71, but from hereon the valve accordingto the embodiment of FIG. 7 will be described without talking thethickness of the damper discs 70,71 into consideration.

When the valve is set for a small air flow, also the total opening y issmall. For very small flows, y is less than x, i.e. all suspension means73,74 are collapsed, and the damper discs 70,71 rest against the flowreducing device 18. In this setting it is the upper most damper 70,which by its upper surface forms the damper surface 76. For increasedflow the flow reducing devise 18 and the tube are displaced away fromeach other, in the illustrated embodiment by displacing the dynamic tubemember 12 into the stationary tube member 11. When y exceeds x the firstsuspension means 73 will be stretched and lift with it the upper damperdisc 70. When the opening y is more than x but less than 2x, the lowerdamper disc 71 will remain against the flow reducing device 18.Therewith, the total opening y will be split into two openings: an upperopening with height x, limited by the flange surface 31 and the upperdamper surface 76 of the upper damper disc 70, and a lower opening withheight y-x, limited by the lower damper surface 77 of the upper damperdisc 70 and the upper damper surface 78 of the lower damper disc 71. Ifan increased flow is desired the tube member 12 is displaced further upsuch that also the second damper disc 71 is lifted by its suspensionmeans 74, which is the case illustrated in FIG. 7. Therewith the totalopening y will be split into three openings, if y is larger than 2x andsmaller than 3x, were the upper opening is unaltered from the case wheny is larger than x but smaller than 2x. The middle opening will, just asthe upper opening, be of height x, defined by suspension means 74. Thelowest opening will be limited by the lower damper surface 79 of thedamper disc 71 and the damper surface 19 of the flow reducing device 18,provided that there are no more damper discs devised between the flowreducing device 18 and the flange 30.

Preferably the number of damper discs is selected such that for a fullopening, i.e. when the dynamic tube member 12 basically is displaced allthe way into the stationary tube member 11 until the flange 30 engageswith the ceiling 4 or the mounting flange 20, the entire opening y isdivided into sub-openings each having a maximum height x. An increasedopening from the scenario in FIG. 7 will thereby lead to a new damperdisc being lifted up each time the opening y increases with the heightx.

The arrangement according to the embodiment of FIG. 7 brings about thatindependent of the opening y the air flow will have to pass through anextended flow distance with a predetermined maximum height x, wherein aneven pressure reduction is always obtained. The effect thereof isminimised sound generation throughout the flow interval.

As previously pointed out, this arrangement may also be obtained bymeans of a displaceable flow reducing device according to FIG. 2A.Furthermore, it is realised that the actuator does not have to bedevised with the driver means 22 with the transmission 23,24,25, butthat other types of flow regulation are conceivable. A person skilled inthe arts also realises that the arrangements according to FIG. 7 maylikewise be applied to the embodiments of FIGS. 3–6.

The embodiment of FIGS. 8 a and 8 b are similar to that of FIG. 7, butdiffer in one detail. Instead of arranging the terminal such that onesub-opening is opened at a time, the embodiment of FIGS. 8 a and 8 buses suspension means 80 which open all gaps or sub-openingssimultaneously, and at the same rate. In FIG. 8 a this is illustrated byindex z used for all sub-openings. In the illustrated embodiment, asshown in FIG. 8 b, this function is implemented by the use of a lever80, running in recesses 81 in each damper element 18,30,70,71. In theembodiment of FIG. 8 b these recesses are made as cut-in portions at theouter edges of the damper elements, but the skilled person realises thatthey may just as well be formed on the inner edge, or centrally in thedamper elements. The suspension arrangement according to FIG. 8 b is notillustrated in FIG. 8 a, but one or preferably two or more suchsuspension arrangements are used, preferably evenly distributed aboutthe circumference of the terminal. The specific embodiment of FIG. 8 bhas a lever 80 with an elongated essentially straight mid portion withtwo end portions bent from the mid portion. The mid portion runs throughall of the recesses 81 devised for the suspension arrangement, and eachdamper element rests with an edge section 82 of the recess 81 on thelever 80. Preferably the discs 70,71 are devised with other recesses forthe fixation bars 21, so that the discs can move freely up and down, ina similar manner as previously described for the flange 30. This is ofcourse also valid for the embodiment of FIG. 7. In the embodiments ofFIGS. 8 a and 8 b the recesses (not shown) for the spacer bars 21guarantee that the damper elements will not rotate in relation to eachother, and as a result thereof slide down along the lever towards eachother. The illustrated embodiment where all sub-openings are regulatedsimultaneously and at the same rate brings about that the flow isproportional to the actuator setting.

FIGS. 9 a and 9 b disclose an embodiment of an air supply terminalaccording to the invention for wall mounting. As the embodiments ofFIGS. 8 a and 8 b, the terminal of FIGS. 9 a–9 b uses pluralsub-openings devised to be regulated simultaneously and at the samerate. A tube 11 for supply of air ends in a narrowing space, so that thepressure reduction will not occur before the damper elements, i.e. atthe extended flow distances between the flow reducing device 18, discs70,71 and the bottom surface 90. The flow reducing device 18 isconnected to the tube at one end by a foldable or resilient member 91,e.g. made of rubber. The actuator 20 is devised with a transmission 93to displace the flow reducing device 18 and the damper discs 70,71closer or farther away from the tube 11. By an integrating element, inthe drawing exemplified with pins 92 fixed to one of the damper discs70,71 or the flow reducing device 18 and running freely throughcorresponding holes 94 in the other displaceable members, thedisplacement of the flow reducing device 18 and the discs 70,71 is donesimultaneously. FIG. 9 b illustrates this embodiment from above, whereasFIG. 9 a is a side view through section A—A. The discs and the flowreducing device are devised with protruding pins 97,98 at the sides,engaging with guide surfaces 95 and 96 firmly arranged in relation tothe actuator 20 and tube 11. Each disc and the flow reducing devicepreferably has two pins per side, devised to slide against each oneguide surface, in order to displace the disc or flow reducing devicevertically when pulled or pushed horizontally. Preferably, asillustrated by FIG. 9 a, the guide surfaces have different angles,selected such that each sub-opening will alter equally upon displacementof the discs and the flow reducing device for flow regulation purposes.Needless to say, the embodiment of FIGS. 9 a and 9 b is just one exampleof how to implement the features of the present invention on a wallmounted terminal, whereas the skilled person will surely think ofalternatives within the same inventive concept.

An advantage with the terminal having plural sub-openings with narrowgaps is that the previously described hose effect is obtained throughouta large interval or range of flows. One narrow and extended flowdistance, as illustrated in FIGS. 2A–6, wherein the length of the flowdistance is considerably less than its width, preferably 10 times ormore, brings about the effect that the retardation of the air isobtained through an extended wall friction with a small pressuregradient in the flow direction. When regulating the width of that singlegap within reasonable limits, which dependent on the input pressurecould be from 0 to a couple of millimetres for a flow distance of acouple of centimetres, the flow will vary with an essentially constantoutput speed of the air. Since the pressure drop will not fall over anedge, as in prior art supply air terminals, there will not be aconcentrated turbulence effect causing the air to lose speed and simplydrop down. However, when the gap increases the hose effect fades, andeventually the edge at the output opening 17 where the tube 11,12 endswill cause the major pressure reduction, with an increased noise as aresult. In order to avoid this problem, i.e. to be able to retain thehose effect throughout a larger flow interval, a multiplication effectis used in accordance with the embodiments of FIGS. 7–9 b. In preferredembodiments according to the drawings of FIG. 7–9 b, three or more gapsor sub-openings are used. Dependent on the pressure of the input air theair terminal is adjusted to the desired flow, e.g. around 30 l/s. Themulti-gap construction of these embodiments is capable of working with awide range of input pressure. The extended flow distance defined by thelength of its delimiting damper elements 18,30,70,71, are preferablybetween 50 and 150 mm, and in one embodiment between 70 and 100 mm. Foran embodiment according to FIG. 7 or 8 a, this would mean that thedamper discs 70,71 have an inner diameter of the central recesscorresponding to or slightly exceeding the inner diameter of the tube11,12, which in one embodiment is about 200 mm. The outer diameter ofthe damper discs 70,71 exceeds their inner diameter by twice the lengthof the extended flow distance, as exemplified above.

For an embodiment having an extended flow distance of about 75 mm and aninput pressure of 20–30 Pa, a flow of 30 l/s is reached at a totalopening of 12–15 mm between the flow reducing device 18 and the flange30, wherein each of the sub-openings have a gap width of 4–5 mm. For aninput pressure of up to 100 Pa, a gap width of 1–1.5 mm is sufficient toreach 30 l/s. Such an embodiment, with a 200 mm tube 11,12, will be ableto control the flow from very low flows of about 4 l/s up to at least 50l/s at 100 Pa, with a maintained high flow speed and resulting throwwith the benefits as explained below, while still keeping the generatednoise to a minimum. With larger tube diameters of 250 mm or more, andpotentially one more damper disc, flows of 70–80 l/s can be obtainedwith the same advantages.

Consequently, in comparison with the prior art technique the presentinvention provides distinct advantages. One advantage is that itprovides the capability to cope with both the problem of noisegeneration and the ability to achieve a good throw of the input airleading to a satisfactory mixing of cool air, meaning that a largertemperature difference between input air and present ambient temperaturecan be used. The multi-disc embodiments of FIGS. 7–9 b furthermoreprovide solutions for obtaining these advantages throughout a large flowinterval. An air supply terminal embodied according to the inventionwill hence both save energy and provide a satisfying indoor climate atlow cost. The design makes it possible to supply air as cool as 15° C.throughout the entire range of flows without causing dropping air ordamping noise at low flows. In one embodiment the invention comprisesone or more circular, ring-shaped discs or sheets, the distance betweenwhich is controlled such that the flow is regulated to the desiredmagnitude dependent on the current need. By forcing the input air toflow through the discs with a lot of wall contact with the surfaces ofthe discs, in comparison with the flow cross section, a gradual pressurereduction is obtained distributed along the entire flow distance throughthe discs. This way no or little sound or noise is generated contrary towhen the pressure reduction occurs over a short distance, e.g. over anedge of a throttle damper. By using multiple discs the maximum flow canbe adapted to a certain room size. In one embodiment, illustrated inFIGS. 8 a and 8 b, the distance or gap between the discs is increased ordecreased to an equal extent during flow regulation. This results in anoptimum function for adapting the gap size in dependence of the airpressure in the supply conduit or duct. At high pressure, ca 100 Pa,small gaps will give the same flow as a lower pressure with larger gaps.That the air supply terminal can be used for high pressure applicationsin the supply system without causing noise is an important advantage,considering that most present facilities are devised to work with apressure of 80–90 Pa.

Another important advantage is that the air speed at the output endopening becomes almost constant independent of the magnitude of theflow, which can range from 4–75 l/s. This means that there will be nocold air dropping effect at low flows. The output speed is alsoimportant due to the resulting high self injection of the input air withthe existing air present at the ceiling, which in turn has the effectthat 90% of the heat exchange occurs at the ceiling, as proven by tests.The air speed decreases with proportionally with the distance from theterminal, and when it hits the wall of a medium sized office room itwill already have been reduced to 0.2 m/s. Furthermore, a verticalrotation swirl is obtained, with the terminal at the centre, which swirlhas an air speed of about 0.1 m/s along the floor. This means that anefficient mixing of the air obtained without resulting in a draft sensedby the people present in the room.

Tests have shown that the cooling effect with a supply air of 15° C. ata flow of 25 l/s is about 300 W, and with 35 l/s the effect becomesabout 400 W. With a supply air temperature of 15° C. the temperature isup to 22° C. at the ceiling already at a distance of 1.2 m from theterminal at a room temperature of 23° C., due to the excellent selfinjection. Furthermore, the sound level from the terminal, as embodiedaccording to FIGS. 8 a and 8 b, will be very low. Test results haveshown <27 dB(A) throughout the entire flow interval. The energyconsumption is reduced since the need for combined heating and coolingis reduced or eliminated, and due to the fact that in many countries thecooler outdoor air can be used during most part of the year for indoorcooling.

By the inventive design, a room size regulator is integrated with thesupply air terminal. It may also control a heat valve sequentially, andmay comprise a passive IR detector capable of increasing the flow frome.g. 4 l/s to 10 l/s, where 10 l/s is a standard measure often used forone person. Even a CO₂ sensor may be connected to and used forregulating the flow of the terminal. The base flow can be setindependently for every room dependent on the heat emission fromdifferent materials, which is a major advantage for e.g. allergicpeople.

In a multi-room facility, such as a school or an office building, theexhaust air is preferably lead to a corridor via air transfer devices,which is extremely favourable from a financial point of view. Even thesound level is lowered about 3 dB(A) due to one less damper being used.The exhaust air from a number of rooms, e.g. 10–15, is flow balanced inthe corridor.

The extended flow reduction according to the present invention,implemented by the flow reducing device 18, the flange 30, damper discs70,71 and or the static reducer 34, results in the air pressure beingreduced gradually, wherein the air resistance or turbulence is evenlydistributed along the entire flow distance, whereby generation of soundis reduced to a minimum. As a consequence thereof the valve is capableof reducing and cutting off flows with an applied air pressure of morethan 100 Pa. Thanks to the flow out from the valve not being impaired bythe same turbulence effect as for valves according to the prior art, thevalve according to the present invention is capable of spreading cooledair of about 16–17° C. along the ceiling with a throw of up to 1.5meter. The flow is preferably controlled dependent on the needs fromonly a few l/s to more than 70 l/s, for example by means of sensorsadapted to sense temperature, amount of CO₂, and so on. The inventionmay thus be formed to manage ventilation adapted to the needs for theentire present existence of office premises, schools and so on, as wellas all new production. It has therefor the qualifications to constitutean important component in a system solution for substantial reduction ofthe energy need for the future.

It should however be noted that the valve construction according to thepresent invention is not limited to the regulation of air flows, but isalso usable for any other gas. It is also apparent that the examples ofdimensions given are not to be interpreted as limiting, but merely asexamples in order to clarify the description. A person skilled in theart further realises that even though not illustrated in the drawingsseveral of the described embodiments may be combined in different wayswithin the scope of the appended claims. This includes, e.g. theapplication of plural damping elements using intermediate discs 70,71 inembodiments with conical damper surfaces, and in valves adapted forimplementation intermediate two joined tubes.

1. A valve comprising: a tube with an axial input opening and a radialoutput opening; a flow reducing device having a damper surface facingsaid output opening for regulation of air flow through said tube; anactuator configured to adjust the distance between the damper surface ofthe flow reducing device and said output opening; a damper flange, whichextends outwardly from edge of said output opening and defines a flangesurface facing the damper surface, wherein an extended flow distancehaving a height between said flange surface and said damper surface isformed; and a damper disc that is configured to have a central recess,the damper disk essentially parallel to and between said damper flangeand the flow reducing device to define parallel and extended flowpassages with sub-openings between said flange surface and said dampersurface.
 2. The valve according to claim 1, further comprising asuspension element connected to the damper disk, the suspension elementconfigured to limit height of the sub-opening for each flow passage tono more than a predetermined maximum height.
 3. The valve according toclaim 2, wherein the suspension element is further configured toposition said damper disc adjacent at least one of said flange surfaceand said damper surface when the distance between said flange surfaceand said damper surface is less than said predetermined maximum height.4. The valve according to claim 2, wherein the suspension element isfurther configured to position said damper disc at said predeterminedmaximum height from at least one of said flange surface and said dampersurface when the distance between said flange surface and said dampersurface is greater than said predetermined maximum height.
 5. The valveaccording to claim 1, wherein said damper disc has a flat ring-shapedportion facing said flange surface of said damper flange, and furthercomprising means for varying a distance between the flange surface andsaid damper disc to adjust a width of the extended flow passages of saidsub-openings and flow through the valve.
 6. The valve according to claim1, further comprising a plurality of damper discs in parallel betweenthe damper flange and the flow reducing device.
 7. The valve accordingto claim 6, further comprising means for limiting the distance betweenadjacent ones of said plurality of damper disks to said predeterminedmaximum height.
 8. The valve according to claim 1, wherein said damperdisc is mounted to said damper flange by a collapsing suspensionelement.
 9. The valve according to claim 1, wherein said tube comprisesa dynamic tube member with opened ends, displaccably arrangedconcentrically with said stationary tube member, wherein said actuatoris configured to displace said dynamic tube member along the stationarytube member to adjust the distance between said output opening and saiddamper surface.
 10. The valve according to claim 9, wherein said flowreducing device comprises spacer bars arranging the damper surface at apredetermined distance from said stationary tube member.
 11. The valveaccording to claim 1, further comprising a suspension element connectedto the damper disk, the suspension element configured to adjust heightof the sub-opening for each flow passage simultaneously so as to adjustoutput fluid flow from the valve.
 12. The valve as recited in claim 11,wherein the suspension element is further configured to adjust theheight of the sub-opening for each flow passage at the same rate. 13.The valve according to claim 11, wherein the suspension elementcomprises a lever which interconnects the tube, the damper disk, and theflow reducing, device.
 14. A valve comprising: a tube with an inputopening and an output opening; a flow reducing device having a dampersurface facing said output opening for regulation of air flow throughsaid tube; an actuator entirely contained within said tube andconfigured to adjust the distance between the damper surface of the flowreducing device and said output opening; a damper flange, which extendsoutwardly from an edge of said output opening and defines a flangesurface facing the damper surface, wherein an extended flow distancehaving a height between said flange surface and said damper surface isformed; and a damper disc that is configured to have a central recess,the damper disk essentially parallel to and between said damper flangeand the flow reducing device to define parallel and extended flowpassages with sub-openings between said flange surface and said dampersurface.